bjoernager/rust
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Targeted fixes addressing erroneous suggestions

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This commit is contained in:
Michael Goulet 2022-08-17 06:48:09 +00:00
parent 6848ba2665
commit 8917894fda
7 changed files with 29 additions and 39 deletions
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36
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
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@ -671,11 +671,16 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
trait_pred: ty::PolyTraitPredicate<'tcx>,
) -> bool {
// It only make sense when suggesting dereferences for arguments
let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = obligation.cause.code() else {
return false;
};
let param_env = obligation.param_env;
let body_id = obligation.cause.body_id;
let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = obligation.cause.code()
else { return false; };
let Some(typeck_results) = self.in_progress_typeck_results
else { return false; };
let typeck_results = typeck_results.borrow();
let hir::Node::Expr(expr) = self.tcx.hir().get(*arg_hir_id)
else { return false; };
let Some(arg_ty) = typeck_results.expr_ty_adjusted_opt(expr)
else { return false; };
let span = obligation.cause.span;
let mut real_trait_pred = trait_pred;
let mut code = obligation.cause.code();
@ -687,9 +692,19 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
// Skipping binder here, remapping below
let real_ty = real_trait_pred.self_ty().skip_binder();
if self.can_eq(obligation.param_env, real_ty, arg_ty).is_err() {
continue;
}
if let ty::Ref(region, base_ty, mutbl) = *real_ty.kind() {
let mut autoderef = Autoderef::new(self, param_env, body_id, span, base_ty, span);
let mut autoderef = Autoderef::new(
self,
obligation.param_env,
obligation.cause.body_id,
span,
base_ty,
span,
);
if let Some(steps) = autoderef.find_map(|(ty, steps)| {
// Re-add the `&`
let ty = self.tcx.mk_ref(region, TypeAndMut { ty, mutbl });
@ -697,8 +712,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
// Remapping bound vars here
let real_trait_pred_and_ty =
real_trait_pred.map_bound(|inner_trait_pred| (inner_trait_pred, ty));
let obligation = self
.mk_trait_obligation_with_new_self_ty(param_env, real_trait_pred_and_ty);
let obligation = self.mk_trait_obligation_with_new_self_ty(
obligation.param_env,
real_trait_pred_and_ty,
);
Some(steps).filter(|_| self.predicate_may_hold(&obligation))
}) {
if steps > 0 {
@ -727,7 +744,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
let real_trait_pred_and_base_ty =
real_trait_pred.map_bound(|inner_trait_pred| (inner_trait_pred, base_ty));
let obligation = self.mk_trait_obligation_with_new_self_ty(
param_env,
obligation.param_env,
real_trait_pred_and_base_ty,
);
if self.predicate_may_hold(&obligation) {
@ -855,6 +872,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
_ => return false,
};
if matches!(obligation.cause.code(), ObligationCauseCode::FunctionArgumentObligation { .. })
&& obligation.cause.span.can_be_used_for_suggestions()
{
// When the obligation error has been ensured to have been caused by
// an argument, the `obligation.cause.span` points at the expression